Bench Seat Headrest Height?

Hello all. My son's 72 Duster has the bench seat with the integrated headrests. I've been searching the site for an answer but couldn't find it.

We will be ordering Legendary seat covers for it but we can't tell if it has the 7" or 9" headrests. Research says to measure from the top of the insert to the top of the head rest. The problem is the old covers have no insert. They must have been redone at some point.

Ball parking it, they appear to be 9". Is there another way to tell for sure?

Thanks in advance for any assistance.